Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
  • H01T23/00—Apparatus for generating ions to be introduced into non-enclosed gases, e.g. into the atmosphere

Definitions

• the present invention relates to a device for transporting air with the aid of so-called ion-wind or corona-wind.
• Such a device includes in principle an air flow duct and a corona electrode and a target electrode arranged axially spaced from each other in the air flow duct, said target electrode located downstream of the corona electrode, seen in the desired air flow direction.
• the corona electrode and the target electrode are connected to a respective terminal of a direct-current voltage source, the design of the corona electrode and the potential difference and distance between the corona electrode and the target elctrode being such that a corona discharge occurs at the corona electrode.
• This corona discharge results in air iones having the same polarity as the corona electrode and possibly also charged so-called aerosols, i.e. solid particles or liquid drops present in the air, said particles or drops being charged upon collision with the charged air iones.
• the air iones move rapidly, under influence of the electrical field, from the corona electrode to the target electrode, where they relinquish their electric charge and again become re-charged air molecules.
• the corona electrode can be designed e.g. as a wire-shaped electrode element, said wire-shaped electrode element extending across the air flow duct that has a rectangular or square cross-section, the wire-shaped corona electrode elements being provided transverse to the longitudinal axis of the duct.
• the efficiency of the air transport is directly depending on the product of the ion current, i.e. the strength of the corona current and the distance between the corona electrode and the target electrode. Further the ion current should be as evenly distributed as possible across the whole cross-sectional area of the air flow duct.
• the walls of the air flow duct said walls normally having an insulated inner side and a conducting earthed outer side, exert a disturbing action upon the corona discharge, and thus upon the corona current and the so-called ion-wind.
• exitation electrodes are provided on the inner side of the current carrying surfaces of the air flow duct, the purpose of said exitation electrodes is to improve the conditions for generating the so-called ion-wind in the air flow duct by connecting the exitation electrodes to a suitable voltage.
• This method has a limited effect and rather than solving the problems described above said method creates electrically defined conditions in the duct including well defined electrode elements that in their turn have a screening effect in a more defined way than the dielectric surfaces of the duct. Especially in narrow flow ducts this method of solving the problems is not suitable.
• the aim of the present invention is among other things to provide an air transporting device using so-called ion-wind or corona-wind, said device being free from the problem discussed above, the aim also being to essentially improve the efficiency of the ion-wind device both as regards the air transport and air cleaning as well as regards the simplicity and safety of operation compared to prior art.
• ion-wind so-called ion-wind or corona-wind
• the aim also being to essentially improve the efficiency of the ion-wind device both as regards the air transport and air cleaning as well as regards the simplicity and safety of operation compared to prior art.
• the device includes an air flow duct 1 having rectangular cross-section, a corona electrode 10 being so arranged that the air flow duct extends both upstream of and downstream of the corona electrode 10.
• the corona electrode 10 constitutes of a single, straight wire that extends across the air flow duct along the rectangular cross-section of the duct, the side walls of the air flow duct being made out of insulating material.
• the corona electrode 10 is connected to a terminal of a high voltage source that is positive relative to earth potential.
• Both downstream of and upstream of the corona electrode 10 the side walls of the duct 1 are coated with current carrying coatings, hereinafter named the duct electrode 12 and the duct electrode 14.
• Said electrodes 12 and 14 respectively are electrically insulated from each other and connected to the respective terminal of the high voltage source in such a way that the duct electrode 12, provided downstream of the corona electrode 10, is connected to the opposite terminal of the high voltage source compared to the corona electrode.
• the duct electrode 14 provided upstream of the corona electrode 10 is connected to voltage of the same polarity relative to earth as the voltage of the corona electrode.
• the present invention differs from previously known ion-wind technique e.g. in the way the ion current is produced and the way said current is forced to migrate in the desired air flow direction, i.e. the way to achieve the ion migration distance.
• the ions are generated around or in the vicinity of the corona electrode 10 due to the electronic field that is created between the duct electrode 12 and the corona electrode 10.
• the field concentration around the corona electrode 10 is sufficient to give rise to generation of air iones.
• a d.c. voltage source 11 creates the potential between the corona electrode 10 and the duct electrode 12.
• the iones do not reach the duct electrode 12 due to the insulated interior surface 13 of the duct.
• the iones are forced to spread in the desired air flow direction on one hand due to the repelling forces between the iones and on the other hand due to the field from the corona electrode 10 and the field from the duct electrode 12.
• the migration of the iones in the opposite direction must be prevented.
• this is carried out by the duct electrode 14 with the aid of the electrostatic field that the duct electrode 14 creates upstream of the corona electrode 10, said field effectively repelling the ion clouds and prevents the migration of the ion clouds in the undesired direction, i.e. against the air flow direction through the device.
• the ions terminate their migration through the air duct channel by spreading in the space where the device is located.
• the ion balance in the air flow duct is maintained due to the generation of new air iones around the corona electrode 10 at the same pace as others leave the duct.
• This motion of the iones in the air flow duct they permanently collide with the non-charged air molecules, the electrostatic forces being transferred also to said air molecules that are carried in the desired direction in the shape of a so called ion-wind or corona-wind.
• conductive layer in the present description the expression "conductive" is to be interpreted in view of the circumstance that the layer or the material not is intended to conduct hardly any current and thus its conductivity can be very low and even highly resistive or antistatic.
• Fig.2 shows schematically a further development of the invention according to fig.l.
• a current carrying element is arranged on the inner side of the the air flow duct, said element below being called a target electrode 16 and is in accordance with the disclosed embodiment located downstream of the corona electrode 10 at a distance "a" measured in axial direction of the duct.
• the target electrode 16 extends around the walls of the air flow duct along the entire periphery.
• the target electrode 16 is connected to the negative terminal of a d.c. source 11 and is at essentially the same potential as the duct electrode 12.
• the target electrode 16 can be designed in several different ways, e.g. in the shape of lamellas that are essentially parallell to the air flow direction through the device, said lamellas being provided on or adjacent to the inner walls 13 of the air flow duct in the shape of a net or a perforated surface, a mesh or the like. It is also possible that the target electrode 16 constitutes a part of the so called precipitator, i.e. a part of the air flow duct of the ion-wind device where the separation of charged aerosol particles take place. However, it is essential that the target electrode 16 allows the air flow to pass through the target electrode 16, said target electrode being made out of or coated with material having a certain conductivity. It is also of a certain practical preference to electrically connect the target electrode 16 to the duct electrode 12.
• the efficiency of the device i.e. the air flow velocity, increases significantly in the duct compared to the example according to fig.l.
• the ions terminate their migration on the target electrode 16 where they give off their charge and become neutral air molecules in the same pace as new ions are generated around and in the vicinity of the corona electrode 10.
• the axial distance "a" from the corona electrode 10 to the target electrode 16 is 10 cm and preferably from 13 to 15 cm, also when the air flow duct has a width, measured perpendicular to both the extension of the corona electrode and the desired air flow direction through the duct, of about 3 to 10 cm.
• the air flow duct having a width of 5 cm and the axial distance "a" from the corona electrode 10 to the target electrode 16 being 15 cm, the electrostatic field from the corona electrode hardly or to a very little extent reaches the target electrode 16.
• the screening of the ion clouds is provided in a direction opposed to the desired air flow through the device.
• the duct electrode 14 can be designed in different ways, e.g. in the shape of lammellas allowing the air to pass through and arranged in parallel to each other, as well as a grid or a net being so designed that a current carrying frame is surrounded by an electrically insulating casing.
• the device according to the invention is so far described in connection with an elongated corona electrode arranged transverse to the longitudinal axis of the duct.
• the corona electrode can be designed in accordance with previously known technique or preferably in accordance with both the description below and the characterising features of the invention.
• corona discharge In laboratory tests it has shown that use of a pointed corona is not suitable in connection with so called corona discharge. The reason for this is that positive corona discharge from a pointed electrode after a certain time of use becomes unstable in such a way that the discharge develops into a so called streamer discharge, a phenomen that is similar to a slightly audible luminous arc generating high quantities of ozone.
• the corona electrode is designed by very thin, short threads that prefereably are grouped in a common holder or distributed across the cross-section of the air flow duct at essentially the same axial distance from the target electrode 16, said threads extending with their free ends essentially in the desired air flow direction or, if the corona electrode is designed as a point, said point constitutes of or is coated with platina.
• the corona electrode 10 constitutes of a holder and very thin, short thread-shaped elements extend from said holder, said elements preferably being made out of resilient material and having an extension essentially in the air flow direction.
• the elements are electrically connected to the positive terminal of the high voltage source, either by groups or separately.
• the corona electrode 10 is designed in such a way that it can perform a turning movement around its axis in a way that is not disclosed in detail.
• a device 18 arranged upstream of the corona electrode, seen in the air flow direction.
• the surface of said device 18 is preferably uneven or bumpy in order to achieve effective scraping of the free ends of the electrode element.
• the device 18 preferably constitutes of a screen/scrape. It is not necessary that the device where the corona electrode constitutes of one or more thread-shaped corona elements or one or more points is designed in accordance with fig.3.
• the diameter of the thread is smaller than 0.2 mm, and preferably 0.1 mm, if short, resilient elements are used for said purpose.
• the corona element will establish a frictional contact with suitable elements to remove possible depositions on the free ends of the corona element.
• the present invention increases the efficiency of the ion-wind device by equalizing the ion density measured in the cross-section of the air flow duct.
• Said duct electrode 12 is to be designed as shown in the example of fig.l and 2 or in several different ways like a fully covering surface or coating or a not fully covering surface, i.e. in the shape of a pattern, e.g. net-like.
• Said duct electrode 12 may be mounted on or in the vicinity of the insulated outer walls.
• the part of the duct electrode 12 being connected to one terminal of the high voltage source could be made of current carrying, semi-conductive or antistatic material, preferably a cellulose-based material having different electrical properties or some kind of paint being electrically conductive.
• Said part can also be manufactured from a current carrying material, e.g.
• the duct electrode 12 should preferably be connected to such a potential that the voltage between the corona electrode 10 and the duct electrode 12 is at a level corresponding to the access of voltage.
• the duct electrode 12 is among other things that it is fairly easy to get access to a very high voltage if, as is the case for the duct electrode 12, the connection to the high voltage source does not impose any current load upon the voltage source.
• the duct electrode 12 is preferably electrically connected to a voltage that is more negative relative to the ion potential than the target electrode 16.
• the duct electrode 14 is designed in a similar way but with the difference that the duct electrode 14 should be connected to a voltage closest to the voltage of the corona electrode or higher in order to achieve efficient screening of the migration of the ions in direction upwards, i.e. in direction towards the undesired air flow through the device.
• the parts of the duct electrodes 12 and 14 being connected to the high voltage are due to their design unsuitable to simultaneously constitute the outer casing of the device. Therefore it is suitable to provide a further coating or surface of insulating material and then preferably to coat said coating/surface with an electrically current carrying material that is connected to earth.
• the duct electrode 12 is connected to a negative voltage and the corona electrode to a positive voltage.
• duct electrode 12 and 14 By the presence of the duct electrodes 12 and 14 and their different embodiments a possibility has been created to design ion-wind devices of different embodiments.
• the expression duct electrode 12 and 14 respectively is therefore given a broader meaning than devices built up around physical ducts. Thanks to the new method to initiate in an air flow duct ion migration of even ion density the efficiency of the ion-wind has increased dramatically for a device according to the present invention compared to previously known devices. This ion-wind technique results among other things in a higher pressure generation. It has been shown in laboratory tests that a device according to the characterizing features of the patent claims preferably can be used to cool electronics, e.g. cooling of computer equipment, copying equipment and/or other electrical equipment where the abscence of noise is of great importance for the user or where the need for long and guaranteed operation time is demanded.
• cool electronics e.g. cooling of computer equipment, copying equipment and/or other electrical equipment where the abscence of noise is of great importance for
• the device can of course also be used for air purification and not only for air transportation.
• the precipitator of the device according to the invention can be designed in a way previously described in patent application PCT/SE85/00236 and other applications in the patent portfolio of TL Vent.
• the difference of the preferred embodiment of the present application is the possibility to design screen-protected and very efficient precipitation electrodes.
• the repelling electrode can of course be designed in several different ways.
• the repelling electrode can be made out of both current carrying as well as semi-conductive and also antistatic material, said electrode is not necessarily arranged on the outer side of the air flow duct.
• the repelling electrode can alternatively be located with a target electrode and essentially in parallel with each other in an air flow duct, the repelling electrode being connected electrically to a terminal of the high voltage source and the target electrode to the other terminal of the high voltage source. In certain cases it is suitable to have the latter earthed. It is not necessary that the repelling electrode has the same voltage polarity as the target electrode.
• Said electrode can be located a certain distance further down in an air flow duct than the target electrode and have the same polarity as the corona elecrode.
• the target electrode 16 being electrically connected to one terminal of the high voltage sorce, has to be negative relative to earth potential and negative relative to the potential of the corona electrode.
• the target electrode is electrically connected to earth or a potential close to earth.
• the corona electrode may be connected to positive or negative voltage relative to earth.

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• Electrostatic Separation (AREA)
• Disinfection, Sterilisation Or Deodorisation Of Air (AREA)

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• 1995
  • 1995-04-18 SE SE9501407A patent/SE505053C2/sv not_active IP Right Cessation
• 1996
  • 1996-04-18 US US08/945,789 patent/US5982102A/en not_active Expired - Fee Related
  • 1996-04-18 EP EP96911154A patent/EP0821840A1/en not_active Withdrawn
  • 1996-04-18 AU AU54121/96A patent/AU5412196A/en not_active Abandoned
  • 1996-04-18 WO PCT/SE1996/000502 patent/WO1996033539A1/en not_active Application Discontinuation
  • 1996-04-18 JP JP8531666A patent/JPH11503870A/ja not_active Ceased

Non-Patent Citations (1)

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